Subsurface wellhead and connector



March 17, 1970 w, PETERSEN 3,500,906

SUBSURFACE WELLHEAD AND CONNECTOR Filed May 25, 1958 3 Sheets-Sheet 1 m.ii i l;

INVENTORI I WILLIAM H. PETERSEN HIS ATTORNEY March 17, 1970 w. H.PETERSEN 3,500,906 V SUBSURFACE WELLHEAD AND CONNECTOR Filed May 23,1968 3 Sheets-Sheet 2 INVENTORI WILLIAM H. PETERSEN HIS ATTORNEY March17, 1970 w. H. PETERSEN 3,500,906

SUBSURFACE WELLHEAD AND CONNECTOR Filed May 23, 1968 3 Sheets-Sheet 5INVENTORI WILLIAM H. PETERSEN HIS ATTORNEY United States Patent 3,500906 SUBSURFACE WELLHEAD AND CONNECTOR William H. Petersen, Houston,Tex., assiguor to Shell Oil Company, New York, N.Y., a corporation ofDelaware Filed May 23, 1968, Ser. No. 731,382 Int. Cl. E2111 7/12,33/035 US. Cl. 166-.6 7 Claims ABSTRACT OF THE DISCLOSURE Apparatus formaking a remote operative connection between a floating vessel and anunderwater wellhead assembly. The wellhead assembly and a wellheadconnector lowerable from the vessel include cooperating orienting meansand means to attach guide lines depending from the vessel to theassembly.

The present invention relates to apparatus for use at underwater oilwell locations and, more particularly, to apparatus for making a remoteconnection between a subsurface production wellhead assembly and afloating vessel.

A recent development in the field of oil well drilling is the completionof wells at offshore locations with a wellhead assembly positioned on orclose to the ocean floor out of the way of ships which might otherwisedamage it in the event of collision. Equipment placed on the oceanfloor, however, is exposed to conditions such as the corrosive nature ofthe sea water and the presence of marine life which tends to grow andbecome encrusted on metallic structures below the surface of the water.

It is necessary therefore from time to time to go back into a wellwherever it has been completed for serv cing or work-over operations. Inaddition, the underwater wellhead assembly itself may call for periodicrepair and maintenance. Due to the problems peculiar to underseaoperations of this type it has been necessary to design and developentirely new equipment for this purpose. For example, an underwaterwellhead assembly has been devised which may be readily removed from itsassociated underwater wellhead and raised to the surface for maintenanceor other purposes. An assembly of this nature is disclosed in US. PatentNo. 3,064,735, issued Nov. 20, 1962, to R. J. Bauer et al.

'In accordance with present practice, maintenance or other underseaoperations relating to a producing wellhead assembly are initiated byestablishing guide means, such as guidelines, between the floatingvessel and the well site. A suitable wellhead connector device is thennormally lowered by means of a pipe string along the guide means to thewellhead assembly. After suitable attachment has been made between theconnector and the wellhead assembly and the required disconnectoperations have been performed with respect to the wellhead assembly andthe wellhead, the assembly is pulled up to the vessel along the guidemeans by means of the pipe string. If desired, a new wellhead assemblymay then be lowered along the guide means and operatively attached tothe wellhead and production may be resumed. Alternatively, the originalassembly after inspection and/or repair on board the vessel may bereturned to its operative position on the wellhead along the guidemeans.

The two steps outlined above of (1) establishing guide means between thevessel and the wellhead assembly and (2) lowering the connector onto theassembly are separately often time'consuming and time is an importantconsideration in offshore oil operations due to the large per diemexpenses involved in the rental of barge equipment, wages, etc.Accordingly, it is advantageous to per- 'ice form maintenance andwork-over operations relating to an undersea well as quickly aspossible.

SUMMARY OF THE INVENTION It is therefore a primary object of the presentinvention to provide apparatus whereby a remote operative connectionbetween a floating vessel and an underwater wellhead assembly can bemade at substantially the same time as guideline means are establishedbetween the vessel and the underwater well site.

A further object of the present invention is to provide cooperatingmeans on an underwater wellhead assembly and a wellhead connector toorient said wellhead connector with respect to said wellhead assembly sothat it may be placed into operative engagement therewith.

These objects have been attained in the present invention by providing awellhead connector lowerable from a floating vessel into engagement withan underwater wellhead assembly. Orienting means, including a pin andslot arrangement, is employed on the connector and the assembly toeffect a predetermined relative position with respect thereto. Aftersuch orientation has taken place the conductor and assembly are lockedinto engagement and guideline means, including latch means, are fastenedto upstanding guide post means fixedly positioned with respect to thewellhead assembly.

DESCRIPTION OF THE DRAWING These and other objects of this inventionwill be understood from the following description taken with referenceto the drawing, wherein:

FIGURE 1 is a diagrammatic view taken in longitudinal projectionillustrating a floating drilling vessel positioned at the surface of abody of water with the elements of the present invention shown prior tooperative engagement there'between;

FIGURE 2 is a longitudinal, enlarged, partial crosssectional viewillustrating details of the present invention with the elements thereofbeing positioned prior to operative engagement;

FIGURE 3 is an isometric, enlarged, partial cross-sectional viewillustrating details of the present invention with the elements thereofplaced in operative engagement;

FIGURE 4 is an isometric cross-sectional view illusstrating one form ofentry conduit closure device employed in the present invention;

FIGURE 5 is an isometric exploded view illustrating a portion of analternate form of entry conduit closure device; and

FIGURE 6 is an enlarged frontal view of the apparatus according to thepresent invention.

Referring to FIGURE 1 of the drawing, a drilling vessel or barge 11 ofany suitable floatable type is illustrated as floating on the surface ofa body of water 12 and substantially fixedly positioned over apreselected location by suitable barge positioning means or by beinganchored to the ocean floor 13 by suitable anchors (not shown) connectedto anchor lines 14 and 15. Equipment, of this type may be used whencarrying on operations in water depths varying from about 100 to 1500feet or more. The vessel is equipped with a suitable derrick 16 as wellas other auxiliary equipment needed during well work-over or maintenanceoperations. The derrick 16 is positioned over a slot 17 which extendsvertically through the vessel in a conventional manner. When using theequipment of the present invention, the slot of vessel 11 may be eitherin. Strings of production tubing and 21 are suspended within the wellcasing and extend into the well in the usual manner.

Positioned on base member 18 is a casinghead unit 24 with a wellheadassembly or production control unit 25 attached thereto. Normally, theproduction control unit or wellhead assembly is in fluid communicationwith the production tubing and comprises the necessary piping, valves,chokes, and other equipment normally connected together and mounted onthe top of a well, and known as a Christmas tree, together with thenecessary hydraulic or electrical systems, including pumps, reservoirs,motors, etc., to operate the valves at the head of the well from aremote location. A typical example of a suitable underwater productioncontrol unit or wellhead assembly for use at an offshore well location,and its manner of operation, is shown and described in theaforementioned US, Patent No. 3,064,735, issued Nov. 20, 1962, to R. J.Bauer et al. For purposes of illustration it will be assumed that thewellhead assembly utilized in conjunction with the present inventionwill be similar to that described in the above patent, although it is ofcourse obvious that the present invention could be utilized with othersuitable wellhead assembly designs. Wellhead assembly 25 includes a pairof radially projecting fluid flow handling conduits or productionflowlines 26 and 27 and an upstanding wellhead entry conduit 28. Fluidflow handling conduits 26 and 27 communicate with production tubingstrings 20 and 21, respectively, and are smoothly curved in an are whichwould permit objects, such as through-the-flowline tools to becirculated therethrough into the well.

As may cost clearly be seen with reference to FIGURE 2, upstandingwellhead entry conduit 28 has fixedly disposed therein, such as by meansof plate member 29, connector elements 30 and 31 which comprise lengthsof tubing in communication at their lower ends with production tubingstrings 20 and 21. During the actual well production operation valvemeans (not shown) interrupts the fluid communication between tubingstrings 20 and 21 and their respective connector elements 30 and 31.U.S. Patent No. 3,064,735 may again be referred to for a more detaileddescription of an arrangement of this type.

Wellhead entry conduit 28 differs from that disclosed in theaforementioned patent in that a pair of indents 32 and 33 are disposedin opposition to one another as shown at the upper end thereof in themanner shown in FIGURES 2 and 3. In addition two tapered keyway channelsor grooves 34 and 35 (FIGURE 3) are provided in the outer cylindricalwall of entry conduit 28 for the purpose which will be more fullybrought out below. Preferably, the upper end of entry conduit 28 isclosed by means of a suitable end closure device, such as closure member36, to help protect the interior of the entry conduit from the possibleharmful effects of the sea water, sediment, etc. As may be seen withreference to FIGURE 4, closure member 36 comprises a circular disc 37constructed of rubber or other suitable resilient material which is cutinto a plurality of independently movable wedge members 38. When in theunstressed position illustrated, wedge members 38 form a substantiallyliquidtight seal with one another. Integrally attached to disc 37 is adownwardly depending, circular flange member 39, which is adapted to bepositioned against the inner wall of entry conduit 28 and securedthereto by any desired expedient. The chamber within entry conduit 28which is defined at one end by closure member 36 and at the 4 other endby plate member 29 (FIGURE 2) is preferably filled with non-buoyant oilor grease (not shown) which provides additional protection against theharmful effects of the sea water.

FIGURE 5 illustrates an alternative embodiment of an end closure devicewhich may be used to protect the interior of entry conduit 28. Asopposed to the relatively thick walled, one-piece construction ofclosure member 36, the end closure device may be comprised of aplurality of relatively thin-walled, disc-elements placed inface-to-face contact with one another. FIGURE 5 is an exploded viewshowing two such thin-walled, disc-like elements 40 and 41. As withclosure member 36, disc-like elements 40 and 41 are divided into aplurality of wedge members 42 and 43, respectively. Preferably thevarious disc-like elements comprising the end closure device should beangularly disposed with respect to one another so that the respectivewedge members thereof overlap (as shown in FIGURE 5) to form a moreeffective seal.

Referring once again to FIGURES 1 and 2, a wellhead connector 44 of thegeneral type disclosed in copending U.S. application Ser. No. 731,381,filed May 23, 1968, is shown suspended by means of a pipe string 45 fromvessel 11. The wellhead connector has a frame means depending therefrom,by means of which guideline carrying means 46 and 47 are mounted.Wellhead assembly locating and positioning means including ahydraulically actuated, extensible sonar unit 48 and a television camera49, of conventional design, are also frame-mounted on the connector.With particular reference to FIGURE 2, wellhead connector 44 includes acylindrical body member 50 defining a throughbore into which extendtubing runs 51 and 52. Tubing runs 51 and 52 extend upwardly within pipestring 45 to vessel 11. Preferably the tubing runs 51 and 52 are eachcomprised of individual tubing sections of substantially the same lengthas the sections of pipe comprising pipe string 45 and are attachedthereto by suitable internal frame means (not shown) to form integralunits. An arrangement of this type is disclosed in U.S. application Ser.No. 690,996, filed Dec. 15, 1967. However, the tubing runs may beindependently disposed within and along the length of pipe string 45 ifdesired. In any event, the lower ends of tubing runs 51 and 52 passthrough a mounting plate means 53 and are connected thereto by anysuitable means such as welding. Plate means 53 is integrally attached toa portion 54 of the body member 50 which is mounted for downwardlyextensible axial movement with respect to the rest of the body member.Body member portion 54 is connected to pipe string 45 by means of acoupling member 55.

The body member portion 54 is normally biased by any suitable means,such as spring means (not shown), into the retracted positionillustrated in FIGURE 2. A flange member 56 comprises an integral partof body member portion 54 and a resilient O-ring is preferablyaccommodated thereby which sealingly engages the inner Wall of bodymember 50. The annular space or chamber 57 formed between body member 50and body member portion 54 communicates by means of conduits 58 with aseries of hydraulic accumulators 59 which are fixedly disposed aboutbody member 50. Suitable valve means (not shown) are positioned inconduits 58 to establish or break the fluid communication between theaccumulators 59 and chamber 57 as desired. The actuation of these valveswould be accomplished remotely from vessel 11 many well-known manner. Itis to be understood that the valves referred to above are normallyclosed and upon actuation thereof will open to establish fluidcommunication between chamber 57 and the accumulators 59. Upon suchactuation the hydraulic fluid will act upon flange member 56 forcing thebody member portion 54, tubing runsv 51 and 52, and pipe string 45 in adownward direction whereby the body member portion will be in itsextended position. Rather than using the illustrated arrangement ofaccumulators and valves to pressure up chamber 57, a direct hydrauliccircuit could be provided between chamber 57 and a suitable pressurizedfluid source (not shown) on board vessel '11 through a hydraulic cableextending from the chamber to the vessel.

Latch members 60 and 61, which may be either spring or hydraulicallyoperated, are disposed near the lower end of body member 50 in themanner shown in FIG- URE 2. A portion of each latch member extendsthrough the body member 50 into the throughbore defined thereby.Disposed at a 90 degree angle from latch members 60 and 61 and fixedlypositioned on the inner cylindrical wall of body member 50 is a pinmember 62. If desired, a second pin member (not shown) of similarconstruction may be mounted on the inner cylindrical wall of body member50 in opposition to pin member 62.

The operation of the present invention will now be described. It will beassumed that vessel 11 has been positioned over the approximate locationof the wellhead assembly 25 upon which the desired operations are to beperformed. The most usual method of accomplishing this is by surveyingin on the known site of the well by suitable instruments aboard thevessel. As soon as the well site has been surveyed in and the vessel 11suitably oriented and positioned with respect to the wellhead assembly25 by anchor or other means, the wellhead connector 44 and the otherapparatus frame-mounted thereon are attached to pipe string 45 bycoupling member 55 and lowered from the vessel by adding additionalsections of pipe to the string in the customary manner. This operationcontinues until it is determined that sufficient pipe sections have beenadded to position the connector at a distance from the ocean floor 13somewhat greater than the height of wellhead assembly 25.

At this point the sonar unit 48 and the television camera 49 areactuated and monitored from the vessel. The pipe string 45 and wellheadconnector 44 are then manipulated from the vessel to position them inaxial alignment with wellhead entry conduit 28 as illustrated in FIGURES1 and 2. Pipe string 45 is then further lengthened to lower connector 44into engagement with wellhead entry conduit 28. The cone-shaped element63 which is integrally attached to the lower end of body member 50 willassist in maintaining axial alignment between connector 44 and entryconduit 28 as they are brought into engagement. As the loweringoperation continues, the body member 50 and entry conduit 28 will assumethe relative position shown in FIGURE 3. As may be clearly seen in thatfigure, pin member 62 on body member 50 is ready to enter into thekeyway channel 35 of entry conduit 28. In addition, it will be assumedthat the aforementioned second pin member (not shown) will similarlycooperate with keyway channel 34. Due to the tapered configuration ofthe keyway channels, still further lowering of body member 50 will serveto rotatably orient the wellhead connector 44 with respect to wellheadassembly 25 as shown in FIGURE 6. As is more fully disclosed incopending US. application Ser. No. 731,381, filed May 23, 1968, thelowering of connector 44 is terminated when the top of entry conduit 28comes into contact with stop means 64 (FIGURE 2) defined by the innerwall of body member 50. Latch members 60 and 61 are then actuated sothat they are locked into indents 32 and 33, respectively.

After the wellhead connector 44 has been rotatably oriented with respectto wellhead assembly 25 and locked into engagement therewith as abovedescribed, tubing runs 51 and 52 are axially aligned with connectorelements 30 and 31, respectively. The valves (not shown) in conduits 58are then opened thereby forcing body member portion 54, tubing runs 51and 52, and pipe string 45 in a downward direction in the manner whichhas been described above and is more fully set forth in copending U.S.application Ser. No. 731,381. As is also disclosed in the last referredto application, tubing runs 51 and 52 in this extended position form afluid-tight seal with connector elements 30 and 31, respectively. In theevent an end closure device similar to those shown in FIGURES 4 and 5 isused, the body member portion will pass therethrough, due to theflexibility of the wedge members, as it is extended. Suitable wellwork-over or other operations may then be carried out from vessel 11.

FIGURE 6 illustrates the position assumed by the wellhead connector 44after it has been rotatably oriented and locked into position in themanner previously described. It should also be noted that pipe string 45has been pulled downwardly by virtue of its interconnection with bodymember portion 54. It will be obvious upon inspection of FIGURE 6 thatafter the above-outlined operations have been completed, guidelinecarrying means 46 and 47 are positioned over and axially aligned withvertical guide columns 22 and 23, respectively. Slidably disposed inguideline carrying means 46 and 47 are tubular members 65 and 66 havinglower flanged ends 67 and 68 and apertured top plates 69 and 70,respectively. Guidelines 71 and 72 depending from vessel 11 pass throughthe apertures in the top plates and pass into the interior of tubularmembers 65 and 66 in the manner shown. Guidelines 71 and 72 haveattached to the respective lower ends thereof guideline connector means,such as latching means 73, which may be of any known type. For example,US. Patent No. 3,050,140, issued on Aug. 21, 1962, to W. J. Hayes,discloses latching mechanisms which may be utilized for this purpose.

Guidelines 71 and 72 are each kept under constant tension by suitableapparatus such as winch means (not shown) on vessel 11 as the guidelinecarrying means 46 and 47 are lowered along with wellhead connector 4from the vessel. This tension is maintained until the conhector has beenpositioned on and latched to the wellhead assembly as shown in FIGURE 6.When, however, the operator wishes to attach the guidelines to therespective guide posts the guidelines are allowed to slack from thevessel and the tubular members 65 and 66 with their respective latchingmeans are dropped onto the guide posts. The tubular members 65 and 66perform two main functions during this operation. First, the flangedends thereof serve to guide the latch means onto the guide posts, andsecond, the weight of the tubular members helps to insure firmengagement between the latch means and the associated guide posts asthey are dropped thereon. For purposes of clarifying this last-mentionedoperation somewhat, guideline 71 is illustrated in FIGURE 6 as havingbeen allowed to go slack from vessel 11, thus dropping tubular member 65and latch means 73 into engagement with guide post 22. Guideline 72 isillustrated as still being maintained under tension from vessel 11 withtubular member 65 being maintained upwardly and flanged end 68 thereofbeing held in engagement with the lower end of guideline carrying means47.

After the wellhead connector 44 has been connected as shown in FIGURE 6,and guidelines 71 and 72 have been attached to their respective guideposts 22 and 23, the desired operations may be performed. For example,tools or instruments may be circulated down the well through the tubingruns 51 and 52, through connector elements 30 and 31, and intoproduction tubing strings 20 and 21. The procedure for circulating toolsand instruments through a wellhead assembly of this type, i.e. a Y-branched wellhead assembly, is more clearly set forth in the above-notedUS. Patent No. 3,064,735. If desired, suitable manipulations may becarried out through tubing runs 51 and 52 to close down the well andremove all or a portion of the wellhead assembly 25 to the surface alongguidelines 71 and 72 to perform suitable maintenance or otheroperations. US. Patent No. 3,064,735 also describes an arrangement foreffecting the removal of a wellhead assembly to the surface of a body ofwater for this purpose. It should be noted that upon retrieval of thewellhead connector 44 to vessel 11, integrally connected guidelinecarrying means 46 and 47 cooperate with top plates 69 and 70,respectively, to also remove to the surface tubular members 65 and 66along guidelines 71 and 72, The guidelines, as is readily apparent,permit apparatus of any desired type to be conveyed quickly back andforth between vessel 11 and the well site.

I claim as my invention: 1. Apparatus for making a remote connectionbetween a subsurface production wellhead assembly and a floating vesselon the surface of a body of water, said apparatus comprising first meanspositioned on the floor of the body of water and second means lowerablefrom said vessel into engagement with said first means, said first meanscomprising:

base assembly means under said body of water and fixedly positioned withrespect to said wellhead assembly; guide column means included on saidbase assembly means and extending in a substantially upward direction;said second means comprising:

pipe means operatively associated with said vessel and having one freeend and one end held in operative engagement by said vessel; wellheadconnector means afiixed to said pipe means at the end of the pipe meansremote from the vessel; frame means depending from said Wellheadconnector means; guideline connector means depending from said framemeans; guideline means extending from said vessel and being operativelyattached to said guideline connector means; cooperating orienting meanshaving first and second portions, the first portion being carried bysaid wellhead assembly and the second por tion being carried by saidwellhead connector means, said cooperating orienting means being adaptedto operatively position said wellhead connector means with respect tosaid wellhead assembly and position said guideline connector means withrespect to said guide column means so that operative engagement betweensaid guideline connector means and said guide column means may beeffected.

2. The apparatus according to claim 1 wherein said portions of saidcooperating orienting means comprise a guide slot and a pin elementcooperable therewith.

3. The apparatus according to claim 1 wherein saidv wellhead assemblyincludes conduit means and one of said portions of said cooperatingorienting means is operatively associated with said conduit means whilethe other of said portions is operatively associated with said wellheadconnector means.

4. The apparatus according to claim 1 wherein said Wellhead assemblyincludes a plurality of radially pro- 8 5. Apparatus for making a remoteconnection between an offshore wellhead assembly beneath the surface ofa body of water and a remotely-located floating vessel on the surface ofthe body of water, said apparatus comprising:

base assembly means underlying said water and fixedly positioned withrespect to said wellhead assembly, said base assembly means includingguide column means extending in a substantially upward direction;

pipe means depending from said vessel and having Wellhead connectormeans afiixed thereto at the end of said pipe means remote from saidvessel;

guideline connector means depending from frame means on said pipe means,said guideline connector means having guideline means operativelyassociated therewith;

cooperating orienting means on said wellhead assembly and on saidwellhead connector means for operatively positioning said wellheadconnector means on said wellhead assembly and for substantiallysimultaneously bringing said guideline connector means into positionwith respect to said guide column means whereby operative engagement maybe effected therebetween;

means for locking said wellhead connector means to said wellheadassembly after said orienting means has operatively positioned saidwellhead connector means on said wellhead assembly; and

said guideline connector means comprising latching means on saidguideline means for effecting attachment between the guideline means andsaid guide column means after said wellhead connector means has beenlocked to said wellhead assembly and said guideline connector means hasbeen brought into engagement with said guide column means.

6. The apparatus according to claim 5 wherein said wellhead assemblyincludes upstanding conduit means to which the wellhead connector islocked; said conduit means being normally closed at its upper end by endclosure means through which a portion of said connector selectivelyprotrudes.

7. The apparatus according to claim 6 where in said end closure meanscomprises at least one circular disc constructed of resilient materialand including a plurality of independently movable wedge members.

References Cited UNITED STATES PATENTS 3,062,287 11/1962 Hayes l66.53,163,228 12/1964 Hayes l66.5 3,179,176 4/1965 Goepfert 7 X 3,236,3022/1966 Postlewaite 175-7 X 3,316,984 5/1967 Jones 1757 3,322,193 5/1967Word l66.6 3,353,595 11/1967 Nelson et a1. l66.6

FOREIGN PATENTS $34,492 3/ 1958 Germany.

CHARLES E. OCONNELL, Primary Examiner RICHARD E. FAVREAU, AssistantExaminer US. Cl. X.R. 175-7

